Quick-connect expansion coupling for electrical metallic tubing

Abstract

An expansion coupling for interconnecting the terminal portions of separate first and second lengths of electrical metallic tubing to permit relative axial movement between the first and second lengths of electrical metallic tubing. The expansion coupling comprises a sleeve of thin-walled metal tubing having a principal length and an interior axial passageway terminating in opposing first and second openings. The first opening is dimensioned to receive therein in telescopic sliding relation a terminal portion of the first length of electrical metallic tubing. The second opening is dimensioned to receive therein a terminal portion of the second length of electrical metallic tubing. A movable member, such as a set-screw, etc., is positioned proximate the second opening, the movable member being selectively positionable within the axial passageway to secure the second length of tubing in fixed relationship with the sleeve. A stop extends into the passageway to define a limit of telescopic sliding movement for the first length of electrical metallic tubing relative to the sleeve. The coupling is further characterized in that, when a terminal portion of the second length of electrical metallic tubing is received in the second opening and fixedly secured in relationship to the sleeve, the terminal portion of the first length of electrical metallic tubing is freely telescopingly movable within the sleeve to thereby permit relative axial movement between the first and second lengths of electrical metallic tubing.

Description

The present invention relates to couplings such as are employed in creating a movable junction between separate lengths of electrical metallic tubing in a run thereof so as to permit the expansion and contraction of such electrical metallic tubing in response to changes in temperature, etc. More particularly, the present invention relates to such an expansion coupling adapted to facilitate the simple and efficient interrelation thereof with the separate lengths of electrical metallic tubing.It is conventional in many applications to run electric wiring within a relatively thin-walled metal tubing. In large scale installations involving extended runs of such tubing it is commonplace to position what are known as expansion couplings between separate lengths of tubing in order to allow for longitudinal expansion or contraction of the tubing as necessary in response to longitudinal expansion or contraction of the tubing material, such as may be occasioned by variations in temperature (a...

AI Technical Summary

Benefits of technology

The specification describes an expansion coupling for connecting separate first and second lengths of electrical metallic tubing to permit relative axial movement between the first and second lengths of electrical metallic tubing. According to the disclosure, the expansion coupling more particularly comprises a sleeve of thin-walled metal tubing having a principal length and an interior axial passageway terminating in opposing first and second openings. The first opening is dimensioned to receiv

Problems solved by technology

Conventional expansion couplings, including such as described above, are routinely made from rigid metal, making them bulky.

Such couplings are cumbersome to employ and, owing to their multitude of components, expensive to manufacture.

And particularly for indoor applications, where rain, snow, and the like are not a consideration, conventional expansion couplings such as the one described above are unnecessarily complicated in construction and operation.

While advantageous over prior art rigid metal expansion couplings, the Philibert device nevertheless suffers from several drawbacks, most notably in operation.

In consequence, employment of the Philibert device in the field--that is, under actual installation conditions--is rendered problematic by the need to crimp the sleeve following insertion of the lengths of EMT to be joined.

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